Plants clean air to a greater extent than we think

Washington: A new study has revealed that flora plays an unexpectedly important role in cleansing the atmosphere.
The research led by scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, uses observations, gene expression studies, and computer modeling to show that deciduous plants absorb about a third more of a common class of air-polluting chemicals than previously thought.

"Plants clean our air to a greater extent than we had realized. They actively consume certain types of air pollution," said Thomas Karl, the lead author.

The research team focused on a class of chemicals known as oxygenated volatile organic compounds (oVOCs), which can have long-term impacts on the environment and human health.

The compounds help shape atmospheric chemistry and influence climate.

Eventually, some oVOCs evolve into tiny airborne particles, known as aerosols that have important effects on both clouds and human health.

The uptake was especially rapid in dense forests and most evident near the tops of forest canopies, which accounted for as much as 97 percent of the oVOC uptake that was observed.

The team found that when the study trees were under stress, either because of a physical wound or because of exposure to an irritant such as ozone pollution, they began sharply increasing their uptake of oVOCs.

The uptake of oVOCs, the scientists concluded, appeared to be part of a larger metabolic cycle.

"Our results show that plants can actually adjust their metabolism and increase their uptake of atmospheric chemicals as a response to various types of stress. This complex metabolic process within plants has the side effect of cleansing our atmosphere," said Chhandak Basu of the University of Northern Colorado, a co-author.

The results indicated that on a global level plants are taking in 36 percent more oVOCs than had previously been accounted for in studies of atmospheric chemistry.